1 /* 2 * Copyright (c) 2001, 2019, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_GC_G1_G1BLOCKOFFSETTABLE_INLINE_HPP 26 #define SHARE_GC_G1_G1BLOCKOFFSETTABLE_INLINE_HPP 27 28 #include "gc/g1/g1BlockOffsetTable.hpp" 29 #include "gc/g1/heapRegion.hpp" 30 #include "gc/shared/memset_with_concurrent_readers.hpp" 31 #include "gc/shared/space.hpp" 32 #include "runtime/atomic.hpp" 33 34 inline HeapWord* G1BlockOffsetTablePart::block_start(const void* addr) { 35 if (addr >= _space->bottom() && addr < _space->end()) { 36 HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1); 37 return forward_to_block_containing_addr(q, addr); 38 } else { 39 return NULL; 40 } 41 } 42 43 inline HeapWord* G1BlockOffsetTablePart::block_start_const(const void* addr) const { 44 if (addr >= _space->bottom() && addr < _space->end()) { 45 HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1); 46 HeapWord* n = q + block_size(q); 47 return forward_to_block_containing_addr_const(q, n, addr); 48 } else { 49 return NULL; 50 } 51 } 52 53 u_char G1BlockOffsetTable::offset_array(size_t index) const { 54 check_index(index, "index out of range"); 55 return Atomic::load(&_offset_array[index]); 56 } 57 58 void G1BlockOffsetTable::set_offset_array_raw(size_t index, u_char offset) { 59 Atomic::store(offset, &_offset_array[index]); 60 } 61 62 void G1BlockOffsetTable::set_offset_array(size_t index, u_char offset) { 63 check_index(index, "index out of range"); 64 set_offset_array_raw(index, offset); 65 } 66 67 void G1BlockOffsetTable::set_offset_array(size_t index, HeapWord* high, HeapWord* low) { 68 check_index(index, "index out of range"); 69 assert(high >= low, "addresses out of order"); 70 size_t offset = pointer_delta(high, low); 71 check_offset(offset, "offset too large"); 72 set_offset_array(index, (u_char)offset); 73 } 74 75 void G1BlockOffsetTable::set_offset_array(size_t left, size_t right, u_char offset) { 76 check_index(right, "right index out of range"); 77 assert(left <= right, "indexes out of order"); 78 size_t num_cards = right - left + 1; 79 memset_with_concurrent_readers 80 (const_cast<u_char*> (&_offset_array[left]), offset, num_cards); 81 } 82 83 // Variant of index_for that does not check the index for validity. 84 inline size_t G1BlockOffsetTable::index_for_raw(const void* p) const { 85 return pointer_delta((char*)p, _reserved.start(), sizeof(char)) >> BOTConstants::LogN; 86 } 87 88 inline size_t G1BlockOffsetTable::index_for(const void* p) const { 89 char* pc = (char*)p; 90 assert(pc >= (char*)_reserved.start() && 91 pc < (char*)_reserved.end(), 92 "p (" PTR_FORMAT ") not in reserved [" PTR_FORMAT ", " PTR_FORMAT ")", 93 p2i(p), p2i(_reserved.start()), p2i(_reserved.end())); 94 size_t result = index_for_raw(p); 95 check_index(result, "bad index from address"); 96 return result; 97 } 98 99 inline HeapWord* G1BlockOffsetTable::address_for_index(size_t index) const { 100 check_index(index, "index out of range"); 101 HeapWord* result = address_for_index_raw(index); 102 assert(result >= _reserved.start() && result < _reserved.end(), 103 "bad address from index result " PTR_FORMAT 104 " _reserved.start() " PTR_FORMAT " _reserved.end() " PTR_FORMAT, 105 p2i(result), p2i(_reserved.start()), p2i(_reserved.end())); 106 return result; 107 } 108 109 inline size_t G1BlockOffsetTablePart::block_size(const HeapWord* p) const { 110 return _space->block_size(p); 111 } 112 113 inline HeapWord* G1BlockOffsetTablePart::block_at_or_preceding(const void* addr, 114 bool has_max_index, 115 size_t max_index) const { 116 assert(_object_can_span || _bot->offset_array(_bot->index_for(_space->bottom())) == 0, 117 "Object crossed region boundary, found offset %u instead of 0", 118 (uint) _bot->offset_array(_bot->index_for(_space->bottom()))); 119 size_t index = _bot->index_for(addr); 120 // We must make sure that the offset table entry we use is valid. If 121 // "addr" is past the end, start at the last known one and go forward. 122 if (has_max_index) { 123 index = MIN2(index, max_index); 124 } 125 HeapWord* q = _bot->address_for_index(index); 126 127 uint offset = _bot->offset_array(index); // Extend u_char to uint. 128 while (offset >= BOTConstants::N_words) { 129 // The excess of the offset from N_words indicates a power of Base 130 // to go back by. 131 size_t n_cards_back = BOTConstants::entry_to_cards_back(offset); 132 q -= (BOTConstants::N_words * n_cards_back); 133 index -= n_cards_back; 134 offset = _bot->offset_array(index); 135 } 136 assert(offset < BOTConstants::N_words, "offset too large"); 137 q -= offset; 138 return q; 139 } 140 141 inline HeapWord* G1BlockOffsetTablePart::forward_to_block_containing_addr_const(HeapWord* q, HeapWord* n, 142 const void* addr) const { 143 if (addr >= _space->top()) return _space->top(); 144 while (n <= addr) { 145 q = n; 146 oop obj = oop(q); 147 if (obj->klass_or_null_acquire() == NULL) { 148 return q; 149 } 150 n += block_size(q); 151 } 152 assert(q <= n, "wrong order for q and addr"); 153 assert(addr < n, "wrong order for addr and n"); 154 return q; 155 } 156 157 inline HeapWord* G1BlockOffsetTablePart::forward_to_block_containing_addr(HeapWord* q, 158 const void* addr) { 159 if (oop(q)->klass_or_null_acquire() == NULL) { 160 return q; 161 } 162 HeapWord* n = q + block_size(q); 163 // In the normal case, where the query "addr" is a card boundary, and the 164 // offset table chunks are the same size as cards, the block starting at 165 // "q" will contain addr, so the test below will fail, and we'll fall 166 // through quickly. 167 if (n <= addr) { 168 q = forward_to_block_containing_addr_slow(q, n, addr); 169 } 170 assert(q <= addr, "wrong order for current and arg"); 171 return q; 172 } 173 174 #endif // SHARE_GC_G1_G1BLOCKOFFSETTABLE_INLINE_HPP